The model is the generalization of [1]} model. In addition to the solution of [1]} equations for the low-temperature opacities, we solve the induction equation for magnetic field taking into account Ohmic dissipation, magnetic ambipolar diffusion, magnetic buoyancy and the Hall effect. The ionization fraction is calculated following [3]} taking into account thermal ionization, shock ionization by cosmic rays, X-rays and radionuclides, as well as radiative recombinations and recombinations onto dust grains.
